Method and device for applying at least one substance to yarn in motion

ABSTRACT

Apparatus for depositing a substance on threads ( 2, 3, 4; 25; 50, 51, 52 ) in a textile machine is designed in a way such that the substance is deposited in pulses the frequency and/or amplitudes of which are controlled as a function of the speed and/or tension of moving threads ( 2, 3, 4 ).

[0001] The present invention relates to a method and a device for applying at least one substance to moving threads for a textile machine.

[0002] As regards a weaving machine, it is known from the British patent no. 14 82 948 to apply a dye on fillings which are guided from a bobbin to an insertion element. Application is implemented by bringing the filling into contact with a dye, or immersing same in a dye, or spraying the dye on the filling. This design includes a means to consecutively dye the inserted fillings according to a predetermined pattern. It is furthermore known from Belgian patent no. 1,005,751 to apply a dye on a filling while this filling is being inserted into a shed.

[0003] The objective of the present invention is to create a method of the above kind whereby the application of substances on moving threads is improved and in particular is metered more accurately.

[0004] This objective is achieved by predetermining a quantity of a minimum of one substance to be applied per unit length of thread and varying the quantity applied as a function of changes in speed and/or in tension of the moving threads.

[0005] The invention makes it possible to apply a substance at an arbitrary rate on the thread while taking into account changes in speed and/or tension of the moving thread. Illustratively it is feasible in accordance with the invention to apply the substance wholly uniformly on the thread(s), for instance, where the substance is an ink, a dye or another substance, even though the thread is moving at varying speeds.

[0006] In an especially advantageous manner, the invention provides that the minimum of one substance is applied as a sequence of pulses, the repetition rate, i.e. frequency, and/or the amplitude of these pulses being variable. Because the substance is applied in the form of consecutive pulses, rapid response to changes in speed and/or tension of the moving threads is enabled possible.

[0007] In a further embodiment of the present invention, two or more mutually complementary substances may be applied on the same thread. Advantageously the application of the different substances may be varied independently of the other substances. For example, two dye components may be applied that complement each other in the desired thread coloring. Uniform dyeing is feasible that will be independent of speed and/or tension at which the thread(s) is (are) moved is thus feasible.

[0008] In a further embodiment of the present invention, a minimum of one substance is deposited in the form of spray pulses. In an especially advantageous manner, said pulses are implemented piezo-electrically. The frequency and/or the amplitude of the spray pulses may be controlled or regulated in simple manner.

[0009] In a further embodiment of the present invention, a minimum value of pulse frequency is set as a function of the size of the spray jet and of the thread speed. Advantageously the pulse frequency will be larger than 500 kHz. For example, a pulse frequency larger than 500 kHz will allow application of different substances on the same thread. Consequently, a filling may be dyed uniformly during weaving by using different substances each of another color.

[0010] The objective of the present invention also is attained by apparatus fitted with means which feed at least one substance and which is adjustable to feed the substance at a given quantity per unit length on the moving threads and which is connected to a control unit to change the applied quantity of the minimum of one substance as a function of changes in speed and/or tension of the moving threads.

[0011] Further features and advantages of the present invention are elucidated by the description below of the illustrative embodiments shown in the drawings.

[0012]FIG. 1 schematically shows a weaving machine equipped with several devices according to the present invention,

[0013]FIG. 2 schematically shows a section of a device of the invention,

[0014]FIG. 3 is a plot of variable substance application as a function of the speed of a moving thread,

[0015]FIG. 4 schematically shows a weaving machine equipped with the inventive device applying a substance on fillings,

[0016]FIG. 5 schematically shows a weaving machine equipped with the inventive device applying one or more substances on warps,

[0017]FIG. 6 schematically shows a warping machine equipped with several devices according to the invention,

[0018]FIG. 7 schematically shows an Axminster carpet weaving machine equipped with several devices of the invention,

[0019]FIG. 8 schematically shows a knitting machine equipped with several devices of the invention,

[0020]FIG. 9 schematically shows an embroidery machine equipped with several devices of the invention, and

[0021]FIG. 10 schematically shows a tufting machine equipped with several devices of the invention.

[0022] With regard to the weaving machine 1 shown in FIG. 1, fillings 2, 3 and 4 are drawn off by a prewinder set 8, 9, 10 from a set of bobbins 5, 6, 7 and are guided by a thread-tension meter 11 to needles 12, 13, 14 of a thread selection device 15 and then to an insertion system 16. The insertion system contains a delivery gripper 17 receiving a held filling 2 (FIG. 1) and moving it to the center of the shed where said filling passes to a receiving gripper 18 and is moved by it to the opposite side. The delivery gripper 17 and the receiving gripper 18 are driven by a known actuation system (not shown) by means of a drive motor of the weaving machine. The weaving machine 1 moreover includes a control unit 20 and an input unit 21 to feed data to the control unit 20. An encoder 22 associated with the drive motor 19 furthermore is connected to the control unit 20 and detects the angular position of said drive motor 19. The sets of bobbins 5, 6, 7 each are held on a bobbin frame 23. FIG. 1 also shows a reed 24 and warps 25 and fabric 26 formed of warps 25 and fillings 2, 3, 4.

[0023] A device 27 for applying a substance on the fillings 2, 3, 4 is located respectively between the bobbin sets 5, 6, 7 and the associated prewinders 8, 9, 10. The fillings 2, 3, 4 move at variable speeds between the bobbin sets 5, 6, 7 and the prewinders 8, 9, 10. Each prewinder 8, 9, 10 contains an angled arm 28 controlled by the control unit 20 and driven by a motor. The angled arm 28 draws the particular filling from the bobbins 5, 6, 7 and winds it on a drum of the prewinder 8, 9, 10. Due to the weaving pattern and the interruptions arising during weaving, the control unit 20 controls the angled arms 28 at varying speed. Illustratively such a control of prewinder angled arms 28 is known from U.S. Pat. No. 4,715,411 which is incorporated into the present specification. The control unit 20 determining the speed of the angled arm 28 also contains information at any time about said speed.

[0024]FIG. 2 schematically shows a device 27 for applying one or more substances on a filling 2. This device 27 is fitted with several nozzles 29 discharging into a duct 30 wherein a substance can be sprayed onto a moving thread. Each nozzle 29 is fitted with means driven by the control unit 20 to supply the substance in the form of spray pulses to be applied to the filling 2. In the shown embodiment, said means include a piezoelectrtic crystal 31 to which electric pulse voltages are applied by the control unit 20. Said voltage pulses generate displacement pulses of the crystal 31 at predeterminable frequency and predeterminable amplitude. The displacement pulses generated by the voltage pulses assure that a defined quantity of the substance present in a duct 32 shall be present at the outlet of the nozzle 29 and be sprayed onto the filling 2. Each of these ducts 32 of the spray nozzles 29 is connected by a line 33 to a container 34 which is filled with the particular substance. Said substance may be a sizing agent, a dye, an ink, a glue, a varnish, a wax, a lubricant, an elastomer, a plastic, a hardener, a means preparing the thread for dyeing or any other substance.

[0025] In another embodiment, the crystals 31 are replaced by one or several electromagnetically driven plungers driven into and out of the duct 32 at a predetermined frequency and amplitude by electromagnets actuated by the control unit 20. Piezoelectric crystals 31 offer the advantage of enabling the pulses to be driven at frequencies in the MHz range.

[0026] During application, the control unit 20 takes into account the speed at which the filling 2 moves through the apparatus 27. For example, that speed may be determined at which the winding arm 28 winds the thread 2 on the prewinder 8. This speed may be measured either using an encoder mounted on the winding arm 28 or it may be determined from the control signals applied to the motor of the prewinder 8. The substance is sprayed in pulses on the thread 2 as a result of the piezoelectric crystal 31 being fed with voltage pulses from the control unit 20. Illustratively the pulse frequency is predetermined to be proportional to the speed at which the thread 2 moves through the apparatus 27. In this manner, given a defined amplitude, the feed of substance per unit length of thread may be determined in such a way that the same quantity of substance shall be applied on the thread 2 regardless of its speed. The control of the pulse frequency by means of which the substance is sprayed on the thread 2 in relation to its speed offers the advantage that even when the thread speed is changing, the substance always shall be applied at the same rate on the filling 2. In this case, the pulse frequency is varied. However, and in a corresponding manner, the amplitude of the pulses driving the crystal 31 also may be varied. As a result, with the frequency remaining constant, more or less substance may be applied on the thread 2 depending on its thread speed.

[0027] The containers 34 of the device 27, for example, may contain substances A, B, C, D, E, F and G. The substances A through C may be inks, each in a primary color, the substance E may be a white ink, the substance E a black ink and the substance G a varnish, a type of glue, a wax, a lubricant, an elastomer, a plastic or another substance. When dyeing, illustratively a predetermined quantity of ink A and a predetermined quantity of ink B are deposited jointly to impart a secondary color to the thread. To attain a uniform secondary color, the quantities of inks A and B must be selected appropriately.

[0028]FIG. 3 shows a plot 35 of an ink A (or dye A) and a plot 35 of an ink B (or dye B) expressed as a quantity Q related to the thread speed S when a uniform secondary color is uniformly attained. As shown by FIG. 3, comparatively more dye is required to uniformly dye a rapidly moving thread than for the identical but more slowly moving thread. This may be interpreted as a thread being more suitable for more rapid absorption of the dye A than absorption of the dye B. Nevertheless uniform secondary color may still be attained if, for instance, the amplitude of the applied substance pulses is controlled as a function of the thread speed as shown in the curves of FIG. 3. In the illustrated embodiment, the amplitude may be controlled by the piezoelectric crystal 31 extending more or less into the duct 32. The pulse frequency may be the same for both dyes A and B and be proportional to the thread speed. The data of the curves 35 and 36 may be fed through the input unit 21 into the control unit 20.

[0029] Obviously the above described method also applies beyond merely attaining a uniform secondary color. The method of the invention quite easily also applies to attaining controlled and defined color gradations in the thread. For that purpose both the pulse frequency and amplitude may be altered appropriately. Three different fillings 2, 3, 4 are used in the illustrative embodiment of FIG. 1. Alternatively, in order to attain a colored fabric only one bobbin 5, 6 or 7 may be used. As regards different bobbins 5, 6 and 7, another kind of thread for instance may be used, that is, thicker or thinner threads or threads exhibiting different properties.

[0030] Departing from the embodiment of FIG. 1, the embodiment of FIG. 4 shows the apparatus 27 of the invention located between the prewinders 8, 9, 10 and the insertion system 16. The speed at which the fillings 2, 3 or 4 are moved may be determined in a simple manner from the signals of the encoder 22 and from the known but variable transmission ratio of the position of the drive motor 19 relative to the position of the grippers 17, 18 determined by said motor 19. The apparatus 27 then can be controlled in commensurate manner as already described above. As regards the embodiment of FIG. 4, the thread tension of the fillings 2, 3, 4 is additionally measured by the thread-tension sensor 11. The tension in the fillings 2, 3, 4 also affects the rate of dye absorption in a thread. As a rule, the higher the thread tension, the slower the dye absorption. As already discussed above with respect to the speed of the thread, the frequency and/or amplitudes of the pulse-applied substance also may be controlled as a function of thread tension.

[0031] Thread tension also depends on thread speed, and therefore this tension may also be used as a thread-speed parameter. In a preferred embodiment of the present invention, both thread speed and thread tension are taken into account. Moreover FIG. 3 shows a plot 37 of the quantity Q of dye A and plot 38 of the quantity Q of dye B which are required to attain uniform secondary color at given thread speeds when the thread tension is less than shown in plots 35 and 36. The tension is ascertained for instance by the resistance which the thread must overcome when being removed from a bobbin. This resistance varies with the bobbin diameter and as a result, as the bobbin is being unwound. The control units 20 may adjust the frequency and/or the amplitude of the applied substance pulses. Moreover the control unit 20 also may take into account the signals from a sensor detecting the transition from a first used-up bobbin to the next supply bobbin and then initiates the beginning of control parameters of the apparatus 27 by means of the control unit 20.

[0032] Apparatus of the invention also may be used in conjunction with airjet weaving machines wherein fillings are inserted by means of a main nozzle and several auxiliary nozzles into a shed. In this case the filling speed can be measured at shed insertion. Moreover the speed may be measured using sensors detecting the filling moving past certain locations. For instance, a sensor may be located in the region of the prewinder to measure the time interval during which individual turns are drawn off the prewinder.

[0033] The embodiment of FIG. 5 comprises several devices 40 according to the invention applying one or more substances on warps 25. The warps 25 run over a back beam 42. The devices of the invention 40 are mounted between the back beam 42 and harnesses 41. The speed the finished fabric 26 is drawn off a cloth beam 43 determines the speed of the warps 25. Furthermore the displacement of the reed 24 affects the displacement of the warps 25, in particular when the reed 25 beats fillings against the fabric 26. The speed of the warps 25 also varies in the region of the devices 40 while the fillings are beaten by the reed 24 against the fabric 26. In this example the warps will be slightly tensioned and for a brief time will move more rapidly toward the fabric 26, and thereafter they will move back in the direction of the back beam 42. The speed at which the fabric 26 is drawn off also may vary. Conventionally the tension in the warps 25 is measured at the back beam 42. As regards the method of the present invention, and taking into account the changes in speed and/or tension of the warps, the frequency and/or the amplitude of the pulse applied substance is increased at filling beat-up. Directly after filling beat-up, that is when the warps 25 recoil, the deposition of the substance on the warps is stopped at once. The design of the devices 40 corresponds to the embodiment of FIG. 2. However two or more warps 25 may be made to pass jointly through the duct 30 of the apparatus 40, as a result of which a substance shall be simultaneously applied on each of said warps 25.

[0034]FIG. 6 shows a warping machine containing several devices according to the invention 44. This embodiment of a warping machine is especially well suited to make warp beams 45 wherein warps 25 are dyed differently. The warps 25 may be drawn from identical bobbins 47 of a bobbin frame 46. However warp beams 45 with differently dyed groups of threads may be attained, the number of differently dyed groups of threads not being restricted to the number of bobbins in the bobbin frame 46. This machine may be equipped with a simple control system for the frequency and/or amplitude of the pulse-applied substance because the speed and the tension in the warps 26 varies relatively little. Nevertheless when stopping or starting, that is when decelerating or accelerating the warp beams to be made, for example following thread rupture, the speed and tension will rapidly vary, and consequently the method of the invention is especially advantageous to uniformly dye the warps and hence to attain a high-quality warp beam.

[0035]FIG. 7 shows an Axminster carpet weaving machine wherein pile threads 48 are woven by a pile gripper 49 between the basic fabric constituted by warps 25 and fillings into a carpet fabric. The speed and the tension of the pile threads 48 vary rapidly. Because the speed at which the pile is carried along by the pile gripper 49 is known relatively accurately, the method of the invention may be applied in simple manner. One device 27 of the invention is located in the region of each pile thread 48. The frequency and/or amplitude of the substance applied in pulses on the pile thread 48 is controlled during the transport of the pile threads 48 in such manner that pile threads 48 with uniform dyeing is attained. In the simplest embodiment, only one row of pile threads 48 need be used, which then do not require being transferred by means of a selection device to the pile gripper 49 but instead may be transferred to it directly.

[0036]FIG. 8 shows a knitting machine wherein threads from the bobbins 5, 6, 7 are guided to a knitting unit 53. Illustratively the threads 50 and 51 already have been dyed, and accordingly only the fillings 52 are to be dyed by the apparatus 27 of the invention. The fillings 50 through 52 additionally are loaded with sizing agent in the apparatus 27.

[0037]FIG. 9 shows an embroidery machine with embroidering heads 54 and which also is equipped with devices 27 of the invention. Advantageously as regards such an embroidery machine, a lubricant or a varnish may be additionally applied by a device 27 of the invention onto the threads.

[0038]FIG. 10 shows a tufting machine which also is equipped with devices 27 of the invention. In such machines, short thread ends are incorporated in known manner by the tufting heads 55 into a fabric 26. In the process and in the manner already discussed above, a substance is applied by the apparatus 27 of the invention onto the short thread ends.

[0039] The frequency of the pulses by which the apparatus 27 sprays a substance on a thread is determined as a function of the measurement taken in the longitudinal thread direction of a pulse jet and of the number of its units of length that are moved per unit time through the apparatus 27. As regards a weaving machine wherein, for instance, a filling moves at a speed of 25 m/s and where the length in the direction of motion of the thread of a pulse jet issuing from the nozzle is 0.1 mm, a frequency of at least 250 kHz will be required. Advantageously a higher pulse frequency is advantageous to attain uniform colors. Accordingly, as regards weaving machines, a frequency exceeding 500 kHz will be appropriate. In order to attain a secondary color using different spray nozzles 29 each applying a different dye on a thread, a still higher frequency should advantageously be selected, for instance a frequency higher than 2 MHz. Experiments furthermore have shown that as regards comparatively thin threads, the frequency should be increased and selected in such a way that the spacing of substance application between two consecutive pulses will be roughly the size of the thread thickness.

[0040] The invention is not restricted to application pulses of one or more substances as a function of thread speed and/or thread tension. Application in the form of pulses also may be made a function of other thread properties, for instance thread moisture, thread temperature, diameter of the bobbin feeding the thread, thread material properties, material properties of the deposition substances and other properties.

[0041] The invention is especially applicable to the manufacture of fabrics wherein different colors are interwoven. By use of the present invention, the initial fillings and/or warps may be non-dyed and nevertheless a colored fabric may be obtained. As regards weaving machines in particular, such a feature not only is economical because it permits using a comparatively simple weaving machine with only a few channels, but also weaving may be carried out in small batches without incurring high waste of dyed threads that thereafter could not easily be re-used.

[0042] The applicability of the present invention is not restricted to gripper weaving machines or to airjet weaving machines. Instead it is also applicable to other weaving machines, in particular to multiphase weaving machines, weaving rotors, gripper shuttle machines, waterjet machines, projectile weaving machines and other weaving machines. The invention also applies to other textile machinery processing several different threads. The latter illustratively are warp knitting machines, circular knitting machines, sewing machines, also spinning machines and others.

[0043] Moreover the both the method and the apparatus of the invention offer the advantage that they may be carried out and implemented after a few retrofits on extant textile machinery, for example by merely adding a control unit and several supports for the apparatus of the invention.

[0044] The method and the apparatus of the present invention are not limited to the illustrative embodiments described above and shown in the drawings. Instead further variants may be implemented within the scope of the present invention. 

1. A method for applying at least one-substance on moving threads (2, 3, 4; 25; 50, 51, 52) in a textile machine, characterized by predetermining a quantity of a minimum of one substance to be deposited per unit length of thread (2, 3, 4; 25; 50, 51, 52), said applied quantity being varied as a function of variations in the speed and/or the tension of the threads (2,3,4; 25; 50,51,52).
 2. Method as claimed in claim 1, characterized in that the minimum of one substance is deposited in the form of consecutive pulses, the pulse repetition rate, i.e. frequency and/or amplitude, being altered to change the applied quantity.
 3. Method as claimed in either of claims 1 and 2, characterized in that two or more complementary substances are applied on the same threads (2, 3, 4; 25; 50, 51, 52).
 4. Method as claimed in one of claims 1 through 3, characterized in that the minimum of one substance is deposited in the form of spray pulses.
 5. Method as claimed in one of claims 2 through 4, characterized in that the pulses are generated piezo-electrically.
 6. Method as claimed in one of claims 2 through 5, characterized in that a minimum value is set for the pulse frequency as a function of the magnitude of the spray jet and the speed of the threads (2, 3, 4; 25; 50, 51, 52).
 7. Method as claimed in claim 6, characterized in that the pulse frequency is larger than 500 kHz.
 8. Apparatus for applying at least one substance on moving threads (2, 3, 4; 25; 50, 51, 52) in a textile machine, characterized in that it includes means (27, 40, 44) to apply at least one substance and which is adjustable to allow establishing a predetermined substance quantity per unit length of the moving threads (2, 3, 4; 25; 50, 51, 52) to be applied to said threads, said means being connected to a control unit (20) to change said applied quantity of the least one substance as a function of changes in the speed and/or tension of the said moving threads.
 9. Apparatus as claimed in claim 8, characterized in that it includes at least one nozzle (29) to spray the minimum of one substance, said nozzle being controlled electrically and preferably in a piezoelectric manner in order to discharge spray pulses at a variable frequency and/or at variable amplitude.
 10. Apparatus as claimed in either of claims 8 and 9, characterized in that it includes several nozzles (29) which spray in each case another substance on the threads (2, 3, 4; 25; 50, 51, 52) and which preferably are controlled independently from each other by the control unit (20). 